Process for the preparation of acetal esters



l atenteol ct. 5, 1954 STATES ATENT OFFHCE raoosss FOR THE PREPARATION or ACETAL ESTERS corporation of Delaware N Drawing. Application March 30, 1951, Serial No. 218,549

Claims. 1

This invention relates to a chemical process. More specifically it relates to a novel process for the preparation of a higher fatty acid ester of a cyclic acetal.

It is the object of this invention to provide a novel and improved process for the preparation of a higher fatty acid ester of alkylol substituted 1,3-dioxolanes and alkylol substituted 1,3-dioxanes.

The preparation of cyclic acetals of the 1,3- dioxolane and 1,3-dioxane types by the reaction of ketones or aldehydes with polyols in the presence of catalyst is well known. Furthermore, where cyclic ketals of this type contain unsubstituted hydroxyl groups they may be esterified by processes such as described in the United States Patent to Marple No. 2,312,298. Similar cyclic esters may be formed by reacting a ketone with a polyol substituted ester. The term acetal used herein is intended to include the condensation product of a polyol with either an aldehyde or a ketone.

In accordance with the present invention it has een found that a higher fatty acid ester of an alkylol substituted 1,3-dioxolane or an alkylol bstituted 1,3-dioxane can be formed directly, one step, by the condensation of a polyol con- "aining at least three hydroxyls, a ketone or aldeiyde and a higher fatty acid in the presence of an acid acting catalyst without the separation even intermediate formation of either the alliylol substituted cyclic acetal or the polyol substituted ester.

Compounds of the type formed according to the present invention are useful as intermediates in the prepaartion of other organic compounds such as the monoglycerides of the higher fatty acids. They are also useful as solvents, plasticizers, and surface active agents.

The process of the present invention is coniently performed by refluxing a polyol conat least three hydroxyls, a ketone or aldehyde and a higher fatty acid in the presence of an acid acting catalyst at atmospheric pressure. Pressures higher or lower than atmospheric may be, employed, frequently with the advantages of facilitating condensation and/or improving the removal of water formed during the reaction. If the ketone is water immiscible, it may be used in excess to promote azeotropic removal of the wamr formed. Other water immiscible solvents with suitable boiling points such as toluene, xylene and the like, are likewise suitable in this role.

Glycerol and higher polyols containing three or (Cl. MiG-340.7)

more hydroxyls are amenable to the process. Among such aliphatic polyols which are suitable may be mentioned glycerol, pentaglycerol, the tetritols, the pentitols, the hexitols, such as sorbitol, mannitol and dulcitol, hexane pentols and the like. Furthermore, ethers and inner others such as polyglycerol and the hexitans, sorbitan and mannitan may be used.

The polyhydric aliphatic alcohol may be reacted with any saturated aliphatic aldehyde or saturated aliphatic, or carbocyclic ketone or any mixed saturated aliphatic carbocyclic unsubstituted ketone. Those boiling above C., are preferable when operating at atmospheric pressure. Among such ketones are included the dialkyls such as dimethyl, diethyl, dipropyl, diisopropyl, dibutyl, diisobutyl, diamyl, methylethyl, methylpropyl, methylisopropyl, methylbutyl, methylisobutyl, methyl-t-butyl, methylamyl, ethylpropyl, ethylbutyl, ethylisoamyl, propylisobutyl ketone, tridecanone, and carbocyclic ketones such as cyclopentanone, and cyclohexanone and mixed aliphatic carbocyclic ketones such as oyclohexylmethyl, cyclohexylpropyl and the like. Suitable aldehydes include butanal, pentanal, hexanal, heptanal and the like. In general such compounds may be expressed by the formula:

ra es wherein R is a saturated hydrocarbon radical, R represents R or hydrogen and R and B may join in ring formation.

The acids which may be employed include all u of the long chain fatty acids and mixtures of fatty and rosin acids. Those fatty acids containing 11 to 20 carbons are preferred. Among these may be mentioned hendecanoic, lauric, myristic, 'palmitic, stearic, arachidic, oleic, linoleic, and the like. Furthermore, mixtures of fatty acids such as those obtained by the saponification of natural fats and oils may be used as well as mixtures of fatty and rosin acids such as occur in tall oil.

The reaction is performed in the presence of an acid-acting catalyst. Hydrocloric acid, phosphoric acid, p-toluene-sulphonic acid, zinc chloride, potassium bisulfate, iodine and others may be used. As little as 0.25% catalyst based on total charge has been found effective. Larger amounts of catalyst, up to 1%, may be used without detrimental effect. Since it is well known that 1,3-dioxolanes and 1,3-dioxanes are decomposed by high acid concentrations, too great an excess of acid catalyst must be avoided.

3 The following examples are cited to illustrate the invention. They are not intended to limit it in any manner.

Example I A three-necked round bottom reaction flask equipped with two Barrett receivers and an agitator is charged with 263 grams (2.77 mole) of 95% glycerol, 540 grams (5.40 mols) of methyl isobutyl ketone, 710 grams (2.50 mols) of stearic acid and 18 grams (1.0% based on total charge) of 85% phosphoric acid. The mixture is refluxed with stirring for a period of 12 hours. The excess ketone employed serves to remove. water of condensation formed in the reaction mixture. A yield of 35.7% of the stearic acid ester of 2- methyl 2 isobutyl 4 methylo1-1,3-dioxo1ane, based on stearic acid charged, is obtained. The product boils at 189 C. under 0.05 mm. pressure.

Example II The equipment described in Example I is charged as follows:

Glycerol (95%) 465 grams (4.8 mols) Cyclohexanone 588 grams (6 mols) Stearic acid 1136 grams (4 mols) Phosphoric acid (85%)". 13 grams (0.5% based on total charge) This charge is refluxed for a period of two hours and gives a yield of 65% of the stearic acid ester of 2,2-pentamethylene-4-methylol-L3- dioxolane boiling at 210 C., under 0.1 mm. pressure.

Example III A 52.9% yield of the stearic acid ester of 2- methyl-2-ethyl-4-methylol-1,3-dioxolane boiling at 198 C., under 0.6 mm. pressure is obtained by refluxing the following charge for a period of 8 hours in equipment similar to that used above:

Glycerol (95%) 96.8 grams (1.0 mol) Methylethyl ketone 86.5 grams (1.2 mols) Stearic acid 284 grams (1.0 mol) Isopropyl ether 55.0 grams -p-Toluenesulfonic-acii. 2.0 grams (0.4% based on total charge) Example IV 4 dioxolane is obtained. The product boils at 184 C. under a pressure of 0.15 mm.

Example V Pentagylcerol 144.0 grams (1.2 mols) Oleic acid 282.5 grams (1.0 mol) Cyclohexanone 196 grams (2.0 mols) Phosphoric acid (85%) 3.1 grams (0.5% based on total charge) The product distilled at 228 C. at 0.3 mm. pressure.

Many other modifications within the scope of this invention will be apparent to those skilled in the art.

What is claimed is:

l. A process for the production of a higher fattyacid ester of an acetal which comprises condensing in the presence of an acid acting catalyst a saturated, unsubstituted aliphatic polyol containing at least three hydroxyl groups with a higher fatty acid and a carbonylbearing organic compound of the formula:

' References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,312,298 Marple Feb. 23, 1943 FOREIGN PATENTS Number Country Date 559,451 Great Britain Feb. 21, 1944 OTHER REFERENCES I-Iibbert, J. A. C. S., vol. 3'7, July-Dec. 1951. (1748-63). 

1. A PROCESS FOR THE PRODUCTION OF A HIGHER FATTY ACID ESTER OF AN ACETAL WHICH COMPRISES CONDENSING IN THE PRESENCE OF AN ACID ACTING CATALYST A SATURATED, UNSUBSTITUTED ALIPHATIC POLYOL CONTAINING AT LEAST THREE HYDROXYL GROUPS WITH A HIGHER COMPOUND OF THE FORMULA: ING ORGANIC COMPOUND OF THE FORMULA: 